We Keep Coding

How to recheck required input fields in JavaScript/HTML5

I'm trying to stay away from JQuery for this one (nothing against JQuery, I just don't want to load a huge library into this project for something small like this).
I'm curious how I might tell HTML5 to recheck all the required input fields in a given form. For example, I have this form (albeit slightly more complicated but you get the point):
<form action="here" onsubmit="check()">
<input required name="something">
<input type="submit">
</form>
If I don't have anything in that required field, HTML5 shows a popup error, something to the effect of "Please fill in this required field". What is stopping the user from putting in a single space, or some nonsense character like % or >? I'd like to partially validate this client-side (in addition to server side) so it isn't particularly inconvenient when the page redirects to the form submission page and then shows the error, and then goes back to the form, prompting the user to enter everything over again.
Assuming in my onsubmit function check I've removed all whitespace and/or nonsense characters from the ends of the string, how can that function then tell HTML5 to recheck the form to see if the required fields are still not empty?

Instead of onsubmit="check()" use addEventListener.
Now you can do everything with input data.
document.getElementById("submit").addEventListener("click", function(event){
var something = document.getElementById("something").value;
document.getElementById("something").value = something.replace(/[^A-Z0-9]/ig, "");
});
<form action="here">
<input required name="something" id="something">
<input type="submit" id="submit">
</form>

try to use regexp pattern (e.g. exclude white chars: [^\s]*, allow only letters [A-Za-z]*, ...)
<form action="here" onsubmit="check()">
<input required pattern="[^\s]*" name="something" >
<input type="submit">
</form>

Angular form validation with external data binding

I have an Angular 4 form, but with the data tracked in an injected service (for reasons outside the scope of this question).
Each input looks something like...
<input name="..." [ngModel]='getVal(...)' (ngModelChange)='setVal(...)'>
...because there's extra functionality in those getters/setters.
That's working great, but I would also like to use the built-in validation. If I give my form a template reference variable...
<form id="..." #myForm="ngForm">
and look at the value of myForm, it's not tracking any of those inputs. I get that, I mean, I'm specifically telling it to track them elsewhere.
But how can I take advantage of the built in HTML5 validation? i.e. required and pattern

You can use validation like this in your html. This is template based validation as per your requirement.
Submit button will not be active till all the fields are validated.
<form (ngSubmit)="submitFunc()">
<input name="name" [ngModel]='getVal(...)' (ngModelChange)='setVal(...)'
required pattern=""> //required pattern here
<button [disabled]="!myForm.form.valid" type="submit">Submit Form </button>
</form>
You have to add required in your input field and specify pattern with a regular exression.

Trouble adding data-parsley-pattern programmatically

I'm using Parsley, and it's great! I want to add different validators programmatically, depending on locale, using javascript/JQuery. When I hard-code like so:
<input type="text" id="billingPostalCode"
name="userInput_billingPostalCode"
value='<c:out value="${param.billingPostalCode}"></c:out>'
class="form-control" required=""
data-parsley-pattern="^\d{5}(?:[-\s]\d{4})?$"
data-parsley-error-message="Valid Zip/Postal Code Required"></input>
it works great. However, when I try to add it programmatically, it doesn't. I have this in a .jsp file:
<input type="text" id="billingPostalCode"
value='<c:out value="${param.billingPostalCode}"></c:out>'
class="form-control" required=""
data-parsley-error-message="Valid Zip/Postal Code Required">
</input>
And this in .js:
$('#billingPostalCode').attr('data-parsley-pattern', "^\d{5}(?:[-\s]\d{4})?$");
The attribute gets added (I can inspect the element and see it), but it doesn't validate correctly (it sees valid input as invalid). I have tried placing the JQuery code both before and after attaching parsley to the form:
[here...]
$('#paymentInfoForm').parsley( ... );
[and here...]
I have also experimented with the regex, anchored and unanchored, simplified versions, etc. But like I said, the regex works perfectly when it's hard-coded.
Could there be some interference with JSP? Am I missing something? Thanks in advance.

I worked around this by using [0-9] instead of /d in my regular expression. It does seem to be a bug, though. This works as expected:
$('#billingPostalCode').attr('data-parsley-pattern', "[0-9]{5}(?:[-\s][0-9]{4})?");
but the following code not won't validate anything, and will even break hard-coded validation:
$('#billingPostalCode').attr('data-parsley-pattern', "\d{5}(?:[-\s]\d{4})?");
The problem must be specific to javascript, since it works when hard-coded into the jsp file.

AngularJS validation not working correctly

I have some form fields where I only want to allow letters for them to be ('ng-valid'). I have it like the following:
<input type="text" ng-model="Example.field1" ng-pattern="/[a-zA-Z]/" />
It works correctly if you only type in letters, or only type in non-letters, but if they are mixed it won't mark the field as invalid. Can someone tell me why this would be happening? Thanks in advance.

Try this pattern
/^([A-Za-z]+)$/
Right now you are saying that you want one character anywhere in the string.

Angularjs Form/Field validation using JavaScript function without directives

Is there a way to validate a field in angular without using a directive?
For example: I want to make following validation on an input field.
If field is empty we should show "Field must contain a value" message.
if field contains alpha Numeric characters we should show "Field can contain only digits".
An EVEN number - message to the user "Value must be an even number".
I want to make following validation in a call to JavaScript function.
I googled around and saw that there is a way to use ng-valid and $error , however I was not managed to make it work.
Code below is according to one of the answers I got:
<div ng-app>
<form name='theForm' novalidate>
<input type='text' name='theText' ng-model='theText' ng-pattern='/^[0-9]+$/'/>
<span ng-show='theForm.theText.$error.pattern'>Field can contain only digits</span>
<span ng-show='theText.length<1'>Field must contain a value</span>
<span ng-show='theText%2!=0&&document.getElementsByName("theText").value!=""&&!theForm.theText.$error.pattern&&!theForm.theText.$pristine'>Value must be an even number</span>
<br/><input type='submit' value='Submit' />
</form>
I want to take what inside the last [span] and put inside a JavaScript function in order to make it more generic and eventually change only JS and not the HTML when conditions are changing
Can someone please advise? a working example would be great.

I'm surprised no one has mentioned ui-validate
$scope.isOdd = function($value){
return $value % 2;
}
...
<form name="myform">
<input ng-model="myVal" name="value" required
ng-pattern="/^[0-9]*$/" ui-validate=" 'isOdd($value)' "></input>
<pre>{{myform.value.$error|json}}</pre>
</form>
Doesn't get any simpler than that, and it's PROPER AngularJS validation (not silly watches)
Here's a working demo

Take a look at the angularjs form documentation - http://docs.angularjs.org/guide/forms . In general, it is based on the HTML5 attributes like required, min, max, etc.
To get, for example, your first requirement done - "an empty field should show "Field must contain a value" message, yo uwould do something like that:
<input type="text" ng-model="user.name" name="uName" required /><br />
<div ng-show="form.uName.$invalid">
<span ng-show="form.uName.$error.required">Field must contain a value.</span>
</div>
For digits only field you can use the pattern attribute with a matching regular expression (example: http://www.wufoo.com/html5/attributes/10-pattern.html).
For even number validation, I'm not sure - I think you'd have to go with custom validation for that (meaning you'd have to create a directive) or use the pattern attribute somehow.
Last but not least - remember to add novalidate to the <form> tag. Otherwise the browser will try to validate your fields as well and you don't want that:
<form ... novalidate>
...
</form>

I know the question is old and I know you didn't want a directive but you may consider using a directive if it's "Angular" way... Well here is my Angular-Validation. I made a project on Github and I think that it just rocks compare to whatever is/was available...I based myself on the excellent Laravel PHP Framework and made it available under Angular... It is so crazy simple, you need 2 lines 1 line of code, 1 line for the input, 1 line for error display, that's it... never more and never less!!! Enough said, let's give some examples:
<!-- example 1 -->
<label for="input1">Email</label>
<input type="text" validation="email|min_len:3|max_len:25|required" ng-model="form1.input1" name="input1" />
<!-- example 2 -->
<label for="input2">Alphanumeric + Exact(3) + required</label>
<input type="text" validation="alpha|exact_len:3|required" ng-model="form1.input2" name="input2" />
So I can define whatever amount of validation rules (already 25+ type of validators) which I want in a simple directive validation="min_len:2|max_len:10|required|integer" and the error message will always display in the next <span> Don't you guys like it already? 1 line of code for your input, 1 line of code for the error display, you can't be simpler than that...oh and I even support your custom Regex if you want to add. Another bonus, I also support whichever trigger event you want, most common are probably onblur and onkeyup. Oh and I also support multiple localization languages via JSON external files. I really added all the imaginable features I wanted into 1 crazy simple directive.
No more clustered Form with 10 lines of code for 1 input (sorry but always found that a little extreme) when the only thing you need is 2 lines, no more, even for an input with 5 validators on it. And no worries about the form not becoming invalid, I took care of that as well, it's all handled the good "Angular" way.
Take a look at my Github project Angular-Validation... I'm sure you'll love it =)
UPDATE
Another candy bonus! To make an even more smoother user experience, I added validation on timer. The concept is simple, don't bother the user while he's typing but do validate if he makes a pause or change input (onBlur)... Love it!!!
You can even customize the timer as per your liking, I've decided to default it to 1 second within the directive but if you want to customize you can call as for example typing-limit="5000" to make a 5 sec. timeout. Full example:
<input type="text" ng-model="form1.input1" typing-limit="5000" validation="integer|required" name="input1" />
<span class="validation text-danger"></span>
UPDATE #2
Also added input match confirmation validation (ex.: password confirmation), here is a sample code
<!-- input match confirmation, as for example: password confirmation -->
<label for="input4">Password</label>
<input type="password" name="input4" ng-model="form1.input4" validation="alpha|min_len:4|required" />
<label for="input4c">Password Confirmation</label>
<input type="password" name="input4c" ng-model="form1.input4c" validation="match:form1.input4,Password|required" />
UPDATE #3
Refactored the directive so that the requirement of having a <span> to display the error is unnecessary, the directive now handles it by itself, see the code change reflected on top.
DEMO
Added a live demo on Plunker

Well you can try to create a func
<span ng-show='isEven(theText)'>Value must be an even number</span>
$scope.isEven=function(data) {
if(data) {
return data%2===0
}
return true;
}
The method can either be defined on the current controller scope or on $rootScope.
Not a very angular way, as directives would be better but i think it would work.